微波消解-电感耦合等离子体质谱法测定食品中总磷含量

Determination of Total Phosphorus Content in Food by MD-ICP-MS

目的：建立一种测定食品中总磷含量的微波消解一电感耦合等离子体质谱（ICP—MS）方法，为检验工作提供更加快捷，精准的方法。方法：样品中加入HN03和H：0：进行微波消解，以Sc为内标元素，用电感耦合等离子体一质谱仪进行测定。结果：总磷含量在0—10mg／L范围内有良好的线性关系，相关系数为0．9997；对两种实际样品的平均加标回收率范围分别为95．31％～101．48％和97．51％～103．74％；对同一种样品进行精密度测定，相对标准偏差为0．1％；本法最低检出限为0．032mg／L。采集5种样品用国标法与本法作比对实验，经统计学检验P=0．117〉0．05，表明两种方法无显著性差异。结论：所建立的ICP—MS方法准确度高，重现性好、操作简便、大大减少了样品前处理时间，适用于各类食品中总磷含量的测定。

[ Objective] It is to set up a method for the determination of total phosphorous in food by ICP - MS, and provide faster and more accurate method of inspection. [ Method] The samples were microwave -digested by nitric acid （ HNO, ） and hydrogen peroxide （ H2 02 ）. The boron content in the treated sample was determined by ICP - MS with Sc as infernal standard. [ Results] ICP - MS had a good relative linearity for total phosphorous at the range of 0 -10mg/L, and the relevant coefficient R is 0. 9997. The average recoveries of the two spiked sam- ples were 95.31% ~ 101.48% and 97.51% - 103.74%. When one sample was determined for the accuracy of this method, we got its RSD 0.1%. LD （limit detection） of this method was 0.032mg/L. There were five re- suits between two determining methods by GB standard method and ICP - MS. The value of P is 0.117 〉 0.05 through a statistical test. It shows that there was no significant difference between the two methods. [ Conclu- sion ] The microwave digestion technique is cutting down the periods of sample pretreated greatly; ICP - MS has simple operation, good reproducibility and high accuracy. Therefore, this method can be applied in the determi- nation of total phosphorous in food.